Expression Of Igf-1 And Tgf-beta In Rheumatoid Arthritis And O~teoarthritis

Lee, In Hong; Jung, Sung Soo; Bae, Sang Cheol; Yoo, Dae Hyun; Kim, Seong Yoon; Chung, Hyun Kee; Choi, Il Yong

Abstract

OBJECTIVE
In normal tissue, a stable equilibrium between the synthesis and degradation of matrix components, is maintained. It is of interest to understand the influence of local growth factors, such as IGF-I(insulinqike growth factor-I) and TGF-beta on this equilibrium. IGF-beta is a polypeptide with functional and structural hornology to proinsulin. IFG-I plays a part in the growth and development of many tissues during fetal and adult stage, and is implicated in tissue hypertrophy and repair. TGF-beta is a multipotent regulator of cell growth and extracellular matrix synthesis. TGF-beta has a biphasic effect on proteoglycan synthesis and cell proliferation. The aim of our study was to determine whether the IGF-I and TGF-beta were expressed by human synovial tissue and articular chondrocytes.
METHODS
Immunohistochemical analysis regarding the expression of IGF-I and TGF-beta in articular cartilage and synovial tissue was conducted using monoclonal antibody and avidin-biotin complex method.
RESULTS
The results were as follows; 1) The expression of IGF-I and TGF-beta in synovial tissue was diffuse and intense at synovial lining cells, endothelial cells and infiltrating inflammatory cells. But the stain of IGF-I protein was distributed unevenly in the synovial tissue. Expression of these two growth factors in rheumatoid arthritis synovium was higher than that in osteoarthritis tissue. 2) The expression of IGF-I and TGF-beta in articular cartilage was strong at chondrocytes and the intensity of staining was strong especially at cluster of chondro cytes. 3) In cartilage-pannus junction, TGF-beta containing cells were detected throughout the pannus area. The stain of IGF I protein was seen in a similar distribution pattern to that in cartilage-pannus junction. These observations suggest that locally produced IGF-I and TGF-beta have specific roles in the synovial pannus formation site.
CONCLUSION
These observations suggest that locally produced IGF-I and TGF-beta have specific roles in the lesions of articular cartilage and synovial tissue. Further prospective in the field of IGF-I and TGF-beta may be the identification of exact pro cess of intracellular signalling and regulation of expression by other cytokines and grwoth factors.